EEVblog Electronics Community Forum
Electronics => RF, Microwave, Ham Radio => Topic started by: caillou on January 19, 2024, 03:17:15 am
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Hi all,
I was wondering if there were RF splitters out there that didn't just passively split by powers of two, but rather tunable ratios? For example 100 W -> 30 W/70 W in one tuning, 40 W/60 W in another tuning, with theoretically 0 degree phase difference. Little loss would be a plus.
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You can look at the unequal Wilkinson splitter (and it's lumped element equivalent)
https://www.microwaves101.com/encyclopedias/unequal-split-wilkinson-power-divider-simplified (https://www.microwaves101.com/encyclopedias/unequal-split-wilkinson-power-divider-simplified)
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Thanks! If we want it to be electrically tunable, say in the lumped elements model, we could use variable capacitors (perhaps in the form of biasing varactors)? Is it fair to say that by tuning the ratio, the phase between the outputs would most likely change as well? What sort of compensation would I need to keep the phase difference close to 0?
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The math for turning the transmission lines into lumped elements can be found here:
https://baltic-lab.com/2014/09/lumped-element-wilkinson-splitter-combiner-design/
You can see that making it adjustable will not be easy since there's at least 5 components that need to be tuned. Can I ask what you're using it for?
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Trying to inductively heat multiple coils with one power amplifier and vary the power delivered to each load using a single RF splitter. Would be nice if the outputs can maintain the same phase too